The basics of crystallography and diffraction (3rd Edition)

vi Preface to the First Edition (1997)
nothing more than an extension of Bragg’s law. Finally, the important X-ray and electron
diffraction techniques from polycrystalline materials are covered in Chapter 10.
The Appendices cover material that, for ease of reference, is not covered in the text.
Appendix 1 gives a list of items which are useful in making up crystal models and provides
the names and addresses of suppliers. A rapidly increasing number of crystallography
programs are becoming available for use in personal computers and in Appendix 2 I have
listed those which involve, to a greater or lesser degree, some ‘self learning’ element. If
it is the case that the computer program will replace the book, then one might expect that
books on crystallography would be the first to go! That day, however, has yet to arrive.
Appendix 3 gives brief biographical details of crystallographers and scientists whose
names are asterisked in the text. Appendix 4 lists some useful geometrical relationships.
Throughout the book the mathematical level has been maintained at a very simple
level and with few minor exceptions all the equations have been derived from first
principles. In my view, students learn nothing from, and are invariably dismayed and
perplexed by, phrases such as ‘it can be shown that’—without any indication or guidance
of how it can be shown. Appendix 5 sets out all the mathematics which are needed.
Finally, it is my belief that students appreciate a subject far more if it is presented
to them not simply as a given body of knowledge but as one which has been gained by
the exertions and insight of men and women perhaps not much older than themselves.
This therefore shows that scientific discovery is an activity in which they, now or in
the future, can participate. Hence the justification for the historical references, which, to
return to my first point, also help to show that science progresses, not by being made more
complicated, but by individuals piecing together facts and ideas, and seeing relationships
where vagueness and uncertainty existed before.
Preface to the Second Edition (2001)
In this edition the content has been considerably revised and expanded not only to
provide a more complete and integrated coverage of the topics in the first edition but
also to introduce the reader to topics of more general scientific interest which (it seems
to me) flow naturally from an understanding of the basic ideas of crystallography and
diffraction.
Chapter 1 is extended to show how some more complex crystal structures can be
understood in terms of different faulting sequences of close-packed layers and also
covers the various structures of carbon, including the fullerenes, the symmetry of which
finds expression in natural and man-made forms and the geometry of polyhedra.
In Chapter 2 the figures have been thoroughly revised in collaboration with
Dr K. M. Crennell including additional ‘familiar’ examples of patterns and designs
to provide a clearer understanding of two-dimensional (and hence three-dimensional)
symmetry. I also include, at a very basic level, the subject of non-periodic patterns and
tilings which also serves as a useful introduction to quasiperiodic crystals in Chapter 4.
Chapter 3 includes a brief discussion on space-filling (Voronoi) polyhedra and in
Chapter 4 the section on space groups has been considerably expanded to provide
the reader with a much better starting-point for an understanding of the Space Group
representation in Vol. A of the International Tables for Crystallography.